For easier reference to the AEM instances involved in these procedures, the following terms are used throughout these articles:

The source instance is the AEM instance that you are upgrading from.

The target instance is the one that you are upgrading to.

What Has Changed?

The following are major changes of note over the last several releases of AEM:

AEM 6.0 introduced the new Jackrabbit Oak repository. Persistence Managers were replaced by Micro Kernels. Starting from version 6.1, CRX2 is no longer supported. A migration tool called crx2oak needs to be run to migrate CRX2 repositories from 5.6.1 instances. For more information, see Using the CRX2OAK Migration Tool.

If Asset Insights is to be used and you are upgrading from a version older than AEM 6.2, assets must be migrated and have IDs generated through a JMX bean. In our internal tests, 125K assets on a TarMK environment were migrated in an hour, but your results may vary.

6.3 has a new format for the SegmentNodeStore, which is the basis of the TarMK implementation. This will require a repository migration as part of the upgrade, involving system downtime. Adobe Engineering estimates this to be around 20 minutes. Note that reindexing will not be necessary. Additionally, a new version of the crx2oak tool has been released to work with the new repository format.

The pre-upgrade maintenance tasks have been optimized to support automation.

The crx2oak tool command line usage options have been changed to be automation friendly and support more upgrade paths.

The post-upgrade checks have also been made automation friendly.

Periodic garbage collection of revisions and data store garbage collection are now routine maintenance tasks that need to be performed periodically. With the introduction of AEM 6.3, Adobe supports and recommends Online Revision Cleanup. See Revision Cleanup for information on how to configure these tasks.

For more details about what has changed in new AEM versions, see the complete release notes:

https://helpx.adobe.com/experience-manager/6-2/release-notes.html

https://helpx.adobe.com/experience-manager/6-3/release-notes.html

Upgrade Overview

Upgrading AEM is a multi-step, sometimes multi-month process. The following outline has been provided as an overview of what is included in an upgrade project and the content that has been included in this documentation:

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